Power transistors commonly employed in automotive and industrial electronics should have a low on-state resistance (Ron·A), while securing a high voltage blocking capability. For example, a metal oxide semiconductor (MOS) power transistor should be capable, depending upon application requirements, to block to drain to source voltages Vds of some tens to some hundreds or thousands volts. MOS power transistors typically conduct very large currents which may be up to some hundreds of amperes at typical gate-source voltages of about 2 to 20 V.
A concept for transistors having a further improved Ron·A characteristic refers to lateral power trench metal oxide semiconductor field effect transistor (MOSFET). Lateral power trench MOSFETs utilize more bulk silicon for reducing Ron so that Ron is comparable to that of a vertical trench MOSFET. In transistors comprising a lateral field plate, the doping concentration of the drift zone may be increased, due to the compensation action of the field plate.
Further developments are being made to improve the characteristics of such a lateral power trench MOSFET. Further, investigations are made to develop a lateral power trench MOSFET which may be contacted from the top side and the back side to implement a vertical device.